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NAME
     ztpcon - estimate the reciprocal of the condition number  of
     a  packed  triangular  matrix A, in either the 1-norm or the
     infinity-norm

SYNOPSIS
     SUBROUTINE ZTPCON( NORM, UPLO, DIAG,  N,  AP,  RCOND,  WORK,
               RWORK, INFO )

     CHARACTER DIAG, NORM, UPLO

     INTEGER INFO, N

     DOUBLE PRECISION RCOND

     DOUBLE PRECISION RWORK( * )

     COMPLEX*16 AP( * ), WORK( * )



     #include <sunperf.h>

     void ztpcon(char norm, char uplo, char diag,  int  n,  doub-
               lecomplex *zap, double *drcond, int *info) ;

PURPOSE
     ZTPCON estimates the reciprocal of the condition number of a
     packed  triangular  matrix  A,  in  either the 1-norm or the
     infinity-norm.

     The norm of A is computed and an estimate  is  obtained  for
     norm(inv(A)), then the reciprocal of the condition number is
     computed as
        RCOND = 1 / ( norm(A) * norm(inv(A)) ).


ARGUMENTS
     NORM      (input) CHARACTER*1
               Specifies whether the 1-norm condition  number  or
               the infinity-norm condition number is required:
               = '1' or 'O':  1-norm;
               = 'I':         Infinity-norm.

     UPLO      (input) CHARACTER*1
               = 'U':  A is upper triangular;
               = 'L':  A is lower triangular.

     DIAG      (input) CHARACTER*1
               = 'N':  A is non-unit triangular;
               = 'U':  A is unit triangular.

     N         (input) INTEGER
               The order of the matrix A.  N >= 0.

     AP        (input) COMPLEX*16 array, dimension (N*(N+1)/2)
               The upper or lower  triangular  matrix  A,  packed
               columnwise  in a linear array.  The j-th column of
               A is stored in the array AP as follows:  if UPLO =
               'U',  AP(i  +  (j-1)*j/2) = A(i,j) for 1<=i<=j; if
               UPLO = 'L', AP(i + (j-1)*(2n-j)/2)  =  A(i,j)  for
               j<=i<=n.   If DIAG = 'U', the diagonal elements of
               A are not referenced and are assumed to be 1.

     RCOND     (output) DOUBLE PRECISION
               The reciprocal of  the  condition  number  of  the
               matrix   A,  computed  as  RCOND  =  1/(norm(A)  *
               norm(inv(A))).

     WORK      (workspace) COMPLEX*16 array, dimension (2*N)

     RWORK     (workspace) DOUBLE PRECISION array, dimension (N)

     INFO      (output) INTEGER
               = 0:  successful exit
               < 0:  if INFO = -i, the i-th argument had an ille-
               gal value

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